The present invention relates to an improved flow rate valve system and valve, especially for axially-rotated valves and includes both apparatus and methods. In particular, the present invention has applicability where a freeze resistant valve is preferred.
Valves have been used for many centuries in a variety of applications. As the technology has progressed, more sophisticated uses have been found for valves. For instance, various improvements have been made in methods of actuation of the valve. Some of these methods include motor driven actuation, solenoid actuation and more recently, computer controlled actuation, and so forth. However, the essential flow design of valves has stayed relatively constant along four basic designs.
One type of valve used is a gate valve. It is simple in design, inexpensive, and can be used in a variety of applications. A gate valve typically contains a circular disk, known as a gate, mounted transverse to a conduit or pipe which engages a seat to block or restrict flow. A gate valve is generally known to those in the art as being poor for controlling flow other than in a fully-opened or fully-closed position. The interface between the gate-and its seat generally erodes and is prone to maintenance.
Another typical valve is known as a globe valve. Those in the art know that it is good for throttling at other than fully-opened or fully-closed positions. An example is shown in U.S. Pat. No. 4,066,090 to Nakajima et al. As can be seen, the flow path is somewhat circuitous resulting in generally higher friction losses, nonlaminar flow, and may prematurely induce flow separation and/or cavitation. Thus, flow rates tend to be less than those of a fully-opened gate valve, the fluid flow path tends to wear, and the globe valve, because of its inherent construction, tends to be bulky.
A third type is a ball valve. The ball valve may offer some advantages of increased flow over the globe valve. The valve actuator connected to the ball is mounted transverse to the flow. As the valve opens, the ball is rotated and aligns a central hole in the ball to the conduit through the valve. The ball valve tends to be somewhat bulky, generally uses two seating surfaces on either side of the ball and may be somewhat expensive to manufacture.
A fourth type of valve is known as a butterfly valve. The butterfly valve has an internal seat that is typically oriented transverse to the conduit. An external valve stem rotates typically a circular disk transverse to the conduit to engage the seat to block fluid flow. A butterfly valve generally has high flow rates and low maintenance. However, it retains the typical construction of a transverse-mounted valve with a transverse valve stem. While the valve stem may be remotely actuated by motors and other devices known to those in the art, it may not be suitable for sealed installations where it might be desirable to completely encase the valve, remote actuator, and seat in a conduit for efficient installation nor is it suitable for installing in a wall structure where access to the actuator is restricted because of the transverse orientation.
An underlying quest in the various designs of valves is a balance between low friction losses, high flow rates, and throttling characteristics. Other considerations may include freeze resistance, simplicity of construction, cost of manufacturing, and perhaps other specialized uses. While there have been numerous variations of the valve types such as described above, there remains a need to provide an improved flow, low friction valve. This may be especially useful in applications where a remote action along a central axis is desired. Typically, these installations involve freeze resistant installations.
In addressing freeze prevention or reduction, efforts have been concentrated on a remote location of a plug of a globe valve away from ambient conditions that could lead to freezing. A typical example is seen in FIG. 7 of U.S. Pat. No. 4,532,954. By remotely locating the plug, the flow of the liquid, typically water, could be stopped a distance in a pipe or a conduit away from the freezing ambient conditions. Those in the art typically concentrated on a globe valve type seat because of the inherent difficulty of actuating a gate valve from within the conduit. In this construction, the nose portion engages a valve seat to seal any flow at a remote location from adverse ambient conditions. As is shown in that figure, the nose must engage a valve seat through the aperture that restricts the flow of water. This remote location results in a beneficial blocking of the water away from the freezing ambient conditions. However, it causes other problems. The wear surfaces may be prone to water erosion and deposits from water impurities. Also, in order to obtain a proper seal, the mechanical advantage of the screw, of the valve stem may, after much use, crush the tip of the nose portion. Once the nose was crushed or deformed, it required even harder tightening of the nose which eventually lead to leaking (the famous xe2x80x9cdrip dripxe2x80x9d). Also, the inherent design of the nose portion, engaging an aperture, causes a significant pressure drop, as those with ordinary skill in the art would immediately recognize. This significant pressure drop reduces flow rates. Reduced flow rates may cause a necessarily proportional increase in the size of conduit, valve, or other devices to obtain the needed flow rates. Additionally, the use of the nose section was a modification of the globe valve type seat which required many turns to suitably seal the flow. Likewise, the valve control rod (stem) moved in the typical longitudinal directionxe2x80x94it was not fixed with respect to the conduit or pipe in which it was assembled. Therefore, increased wear and increased maintenance resulted from not only the rotational movement, but the longitudinal movement as it engaged those portions of the valve seat While an increase in size of the typical valve might achieve the necessary flow rates, typically, this was not a viable option because of size, costs, and compatibility with other components of the piping system.
Thus, prior attempts to remotely seal the water flow or other liquids lead to high pressure drops, low flow rates, and maintenance. The flow rate is especially important in designing sprinkling systems Both residential and commercial sprinkler systems require a higher flow rate than the typical gate valve or globe valve delivers for given typical size. Thus, an installation was not able to use the typical valving of a typical freeze resistant hydrantxe2x80x94instead, it required a direct connection to other piping with sophisticated valving controls. The sophisticated valving, as those with knowledge of sprinkler systems would recognize, required expensive controls, maintenance, purging during off-season uses, local and national codes, and other issues.
A further complication resulted from the axially rotated valves such as the valves referenced above and others such as U.S. Pat. No. 3,848,806 to Samuelsen, et al. This actuation shows that the valve stem on such axially-rotated valves has been heretofore in the flow path. Until the present invention, on such axially-rotated valves, it may have been considered by those in the art that the valve stem was required to be placed in the flow path in order to engage remotely the nose portion to the aperture. However, the additional turbulence and volume contained by the valve stem in the flow path results in additional loss of efficiency, increased resistance and friction, and lower flow rates.
Thus, as systems have become more sophisticated, a need exists for a valve that can be remotely actuated through the internal structure of a valve away from adverse ambient conditions, and yet be inexpensive, easily instaled, of the same or similar diameter to existing piping systems, and still maintain high flow rates and low pressure drops. If a system was available that would allow a high flow rate water hydrant that could be converted to a combination system and water hydrant, it would have an advantage in the market. It would be advantageous to the dwelling owner in a reduction of cost, and it would be advantageous to the builder or installer to simply meet the building requirements of installing outside faucets and yet allow conversion to sprinkler systems at minimal costs.
A significant improvement over the typical valves was attained in the U.S. application Ser. No. 08/637,203, now issued as U.S. Pat. No. 5,718,257, to Robert K. Burgess and upon which this patent claims a priority date. In that patent, it was realized that a fixed longitudinal position with axial rotation could establish high flows and less pressure drop and friction loss and perhaps less maintenance and less costly installations because of its compactness. In that patent, the invention provided a specially designed valve that had a rotatable sealing element longitudinally fixed in position in a conduit which engaged a seating element likewise longitudinally fixed in position in the conduit. The position could be located a sufficient length or distance from for instance, adverse ambient conditions to enable a sealing of flow away from the adverse conditions. That valve significantly improved the flow rates compared to the state of the art known at that time. Test results suggest that the globe valve might have up to approximately 2 times the pressure loss for a given flow rate than the Burgess invention. Similarly, the Burgess invention appears to have about five times less friction loss than the design shown in the ""954 reference above. This invention also allowed a quarter turn from a fully-opened to a fully-closed position. Because of its increased flow, it was felt that it would provide a valve of suitable flow rates that could be installed in the same size as a typical conduit and yet meet even the more demanding sprinkler systems requirements. Among other things, however, that valve retained the typical valve stem located in the flow path.
As an example of the significant improvement in pressure drop by the present invention, FIG. 1a shows the pressure drop as a function of flow rate for various commercially available axially-rotated freeze resistant valves. FIG. 1b shows a graph of measured loss coefficients as a function of Reynolds number for the present invention compared to some commercially available axially-rotated valves and other types of valves, again to show some of the significant improvements of the present invention. The two top curves show valves by competitors, such as are designed for higher flow rates on sprinkler feed systems. Although the ""203 valve appeared to have significant improvement over technology existing at the time, the present invention shows an even greater flow rate for a given pressure drop or conversely a lower pressure drop at a given flow rate. The present invention may have a 4 times improvement over some of the competition when based on pressure drops at a given flow rate.
Another reference, U.S. Pat. No. 286,508 to Vadersen, et al., shows an early attempt in providing an axially-rotated freeze resistant valve. For some reason, the embodiment apparently was not received commercially. Perhaps, two reasons exist. First, the valve plate (G) with apertures (H), when aligned with valve (K) in apertures (T), as those with ordinary skill in the art would readily recognize, would create nonlaminar flow, increased friction loss, flow separation, and perhaps cavitation (depending on the vapor pressure of the fluid at that temperature). Secondly, the valve stem appears located in the flow path. This is in direct contrast to the present invention which in some embodiments uses an axially-rotated split venturi to avoid the problems of the Vadersen reference. Thus, it may be that from the Vadersen reference to the present invention of 114 years, little improvements along this particular line appear to have been thought appropnate.
The present invention goes beyond the inventions of the earlier valves and even the U.S. application Ser. No. 08/637,203, now U.S. Pat. No. 5,718,257. The present invention improves the flow rates for a given supply pressure several times over the ""203 invention. It has a loss coefficient lower than any known axially rotated valve. Its loss coefficient has been tested and may be approximately 50% of a typical axially rotated valve. It may be even simpler to construct, typically avoids the valve stem in the flow path, offers good throttling characteristics, and yet retains higher flow rates for given pressure drops.
Thus, there has been a long felt, but unsatisfied need for the invention that would meet and solve the problems discussed above. The present invention represents the next step in the quest for low friction, high flow and good throttling characteristics, especially in applications where remote actuation of axially-rotated valves is desired. While implementing elements have all been available, the direction of the inventions of other persons have been away from the present invention. The efforts have primarily concentrated on longitudinally moving backward or forward a nose or other sealing element against a valve seat, typically including an aperture. This has resulted in the above-discussed problems, such as poor flow rates. Those in the art appreciated that a problem existed and attempted to solve the problem with technology as shown in U.S. Pat. No. 4,532,954. Even with the improvements of the invention of U.S. Ser. No. ""203, the problem still existed at less than optimal flow rates for given pressure drops. Alternatively, those in the art simply accepted the extra expense of extra installations, complicated valving, and other requirements necessary for such applications as sprinkler systems. This general mind set taught away from the technical direction that the present invention addresses. It might be unexpected that a valve can have significantly higher flow rates and yet remotely control or block the fluid flow with the same or similar size conduit or pipe found in a typical installation and still offer an economical solution until the present invention, it appears that those skilled in the art had not contemplated the solution offered by the present invention.
A primary goal of the present invention is to provide a design which permits increased flow rates for axially-rotated valves, especially those used in freeze resistant prevention valves and sprinkler systems. By recognizing and utilizing the advantages of a wholly different layout and design of a valve, this valve achieves its goals.
The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. (As would be known to those with ordinary skill in the art, a typical venturi is a conical contraction then expansion of a conduit through which a fluid flows. Venturies typically are high efficiency devices primarily used for measuring the flow rates of fluids, see e.g., Beckwith, Thomas, Marangoni, Roy, Lienhard V, John, Mechanical Measurements p. 617 (Addison-Wesley Publ. Co. 5th ed. 1993)). The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. The valve may be designed, in some embodiments, to delay a transition from laminar flow in at least some portion of the split venturi. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses and pressure drop. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane.
Typically, the present invention may be envisioned as useful on residential and commercial installations where it would be desirable to economically reduce the possibility of freezing of the valve. Such applications could also involve sprinkler systems, both underground and above ground. Rather than supplying a system which affords only an incremental increase in performance and design over prior art, the present invention utilizes a technique to achieve significant performance improvement compared to past efforts. The valve of the present invention satisfies one of the criteria by being inexpensive to manufacture and yet offers high flow rates, good maintenance, low pressure drop, and throttling capabilities.
This invention has a significant advantage in the sizing of valves and pipes. It retains the desirability of quickly opening and closing from a fully-opened to a fully-closed position. At a full flow, in some embodiments, the present invention seeks to sustain a streamlined, noncavitating flow, and in some embodiments, a somewhat laminar flow. This may result in less turbulence and reduced friction loss. This invention is particularly important in resolving the difficulties with axially-rotated valves mounted in the flow stream and actuated along a longitudinal axis parallel to a central axis of the valve in a flow direction.
Another goal of the present invention is to provide a design for an axially-rotated valve which permits increased flow rates and less pressure drop using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. An objective of this goal is to provide an axial rotator to rotate at least one of the portions without a substantial engagement of the axial rotator within the flow path. Another goal is to provide an eccentric split venturi approximating the shape of a semicircular cross section in a direction transverse to the flow path which may assist in both throttling capabilities and in maximum flow capacity with the design of the present invention. Such a design can include the object of providing a freeze resistant axially-rotated valve. It may be provided with a length of at least six inside diameters (preferably seven or eight) of the portion, particularly the downstream portion, to assist in providing smooth transitional flow through the split venturi. Another objective may be to provide a cartridge assembly comprising at least part of the valve so that it may be easily retracted and inserted into a conduit of the valve. Such a design may be fully-opened and fully-closed in one-half complete rotation. While this may not be as rapidly opening as the embodiment shown in the ""203 invention, it is believed that such a rapid rotation will satisfy the goals and objectives of the marketplace. Also, the invention may include a purge port adapted to open and allow drainage of the valve when the valve is in at least a partially closed position and typically in a fully-closed position. By using one type of split venturi, the flow rate on the inlet side of the split venturi would include gradually reducing the pressure of the flow as it flows into the first portion of the split venturi and at the same time increasing the velocity of the flow. At the split or interface of the split venturi between the first portion and a second portion, the flow would start to gradually increase in pressure while decreasing in velocity as it flows through the second portion of the split venturi to some exit port. In some instances, the ambient conditions may be such that the conduit itself may provide a conduction path to adverse ambient conditions, such as freezing temperatures. In such instances, it may be beneficial to split the conduit in the freezing area and create a thermal barrier between at least the two portions of the conduit such that the energy is not lost to adverse ambient temperatures. At the interface behind the first portion and second portion, a seal may be used. Such a seal could be adapted to seal the periphery of the interface and in some instances seal diametrically, as will be discussed further. The diametrical seal may be linear or, in some fashion, curvilinear. In some embodiments, the conduit might not be rigid, at least in parts. The conduit might include for instance a flexible tube. A proper location might be such that no interference of the seal between the first and second portions might occur.
Another goal of the present invention is to provide a valve that includes a split venturi between the first and second portion where the portions are non-axisymmetric relative to a central axis. Heretofore, the typical venuri design has been concentric in that at any given cross section the outer periphery is equidistant from a central axis. The present invention abruptly departs from this standard practice by having a non-axisyrtnetric or eccentric venturi that is split in two sections. The two sections may be fluidly connected to one another such as the fluid might flow from one into the other with little change across the interface. Furthermore, such a flow path may be semicircular. By departing from this standard practice of axisymmetric venturis, the present invention is better able to utilize its unique closing and opening capabilities. It is another objective of the present invention to include a rotating internal elbow connected to at least one of the portions that rotates so that as the portion is rotated, the internal elbow can direct the flow into a valve outlet.
Another goal of the present invention is to include an axially-rotated valve using a split venturi having a first and second portion where at least one portion may be rotated by an axial rotator outside of the flow without substantial interference with flow efficiency. One objective of this goal is to provide an axially-rotated valve that is designed to provide streamlined flow (that is, avoiding flow separation and/or cavitation at full flow under a variety of conditions).
Naturally, other objectives of the invention are disclosed throughout other areas of the specification and claims. In addition, the goals and objectives may apply either in dependent or independent fashion to a variety of other goals and objectives in a variety of embodiments.